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Breaking the Light Speed Limit

Howstuffworks

Summary: Once thought to be unbreakable, the speed of light as set by the laws of physics has been exceeded in two recent experiments, according to a New York Times news report.

Once thought to be unbreakable, the speed of light as set by the laws of physics has been exceeded in two recent experiments, according to a New York Times news report. The speed of light in a vacuum, or empty space, is 186,000 miles per second. Exceeding this speed jeopardizes the entire theory of relativity, which rests on the idea that light speed is the universal limit to how fast anything can travel.

Scientists have found ways to break that speed limit. In one experiment performed by researchers at the NEC Research Institute in Princeton, N.J., a pulse of light was sent through a transparent chamber filled with specially prepared cesium gas and was pushed to travel at speeds of 300 times the normal speed of light. The light travels so fast that the main part of the light pulse exits the chamber even before it enters. Theoretically, this means that you could see a moment in time before it actually takes place.

Researchers at the NEC declined to comment on the experiment while it is under review by Nature, a weekly peer-reviewed science journal. However, Kazuko Anderson, a spokesperson with the NEC in New York, confirmed the accuracy of the New York Times report.

In a second superluminal study, published in the May 22 issue of Physical Review Letters, scientists at the Italian National Research Council of Florence shone light beams at a curved mirror. The mirror then shot the beams back at the instrument that measured the rays' speeds. The beam coming from the center of the mirror was measured at 5 percent to 7 percent faster than light speed. The authors said this effect only works over relatively short distances, such as the one meter used by the Italian researchers.

Exceeding the speed of light may have future implications for space travel and computer chips, but for now scientists are uncertain about the practical use of this discovery. Neither experiment was able to use a light beam to carry any information or prove that an object of any weight would be able to travel beyond light speed.